Effects of Modest Hypoxia and Exercise on Cardiac Function, Sleep-Activity, Negative Geotaxis Behavior of Aged Female Drosophila

Abstract

Mild normobaric hypoxia (NH) and modest exercise have multiple beneficial effects on health, but the changes in physiological function induced by NH and/or exercise remain unclear. The purpose of this investigation was to examine the specific effects of NH and/or exercise on cardiac function and myocardial structure and behavior including sleep-activity and negative geotaxis in aged Drosophila. We also assessed the survival rate of flies after hypoxia and/or exercise. One-thousand wild-type w 1118 virgin female flies were randomly divided into four groups and treated with NH and/or exercise from ages 3-6 weeks. We found that exercise remarkably delayed the decline of actin and myosin and the age-related changes in cardiac structure, improved abnormal cardiac contraction, and enhanced the cardiac pumping force by inducing cardiac hypertrophy and delaying deterioration of cardiac contractility and diastolic compliance, and improved abnormal heart contraction. NH also increased the content of actin and myosin, but induced a decrease in heart diameter and heart rate, as well as an increase in the number of mitochondria and deeper sleep, which may be the manifestation of energy saving under long-term hypoxia. Both NH and exercise improved sleep quality and climbing ability of aged flies, as well as extended the maximum life span, which shows the benefits of hypoxia and exercise. Finally, the superposition of NH and exercise did not impart any obvious physiological and behavior improvement. Therefore, it is necessary to further explore the appropriate combination of hypoxia and exercise.

Stable Expression of dmiR-283 in the Brain Promises Positive Effects in Endurance Exercise on Sleep–Wake Behavior in Aging Drosophila

“…Our previous studies demonstrated that prolonged fatigue exercise increases sleep stability and improves sleep quality in aging Drosophila [ 46 , 47 , 48 ], but the regulatory mechanisms remain unclear. Based on the aging change characteristics of sleep–wake behavior, two exercise protocols were designed in this study: exercise starting from young adulthood to middle age (E1), and exercise starting from middle age to old age (E2) ( Figure 5 A), which aimed to investigate the effect of endurance exercise starting at different ages on age-dependent sleep–wake behavior decline.…”

“…In the E1 exercise protocol, we found that endurance exercise increased sleep time in mir-283 SP /+ flies ( Figure 5 C,F). Although activity behavior decreased ( Figure 5 E,J), the activity frequency increased upon awakening ( Figure 5 K), as the activity index (the number of activities per minute) was a better indicator of health in the flies [ 22 , 23 , 48 ], indicating that exercise improved health in middle-aged Drosophila . JTK_CYCLE and CircaCompare analyses indicated that endurance exercise ameliorated age-dependent sleep cycle lengthening, allowing mir-283 SP /+ Drosophila to still maintain a 12 h circadian oscillation with an increased rhythmic amplitude of sleep, activity, and rest ( Figure 5 C–E, Table S3 ), suggesting that endurance exercise initiated in youth maintains a relatively stable sleep–wake rhythm output.…”

Regular Exercise in Drosophila Prevents Age-Related Cardiac Dysfunction Caused by High Fat and Heart-Specific Knockdown of skd

“…In both obese and diabetic rodent models and human subjects, myocardial steatosis is associated with functional and structural changes in the heart [ 44 , 64 ]. In addition, cardiac aging in mammals is always accompanied by disorganized and reduced myocardial fiber arrangement [ 65 ].…”

Early life exercise training and inhibition of apoLpp mRNA expression to improve age-related arrhythmias and prolong the average lifespan in Drosophila melanogaster

“…The Drosophila exercise training device is designed according to Tower power and Swing boat [ 16 , 18 ]. As previously, flies were stimulated to actively walk upwards by flipping the vial for exercise [ 50 ]. In this study, the flies in the exercise group were placed in the exercise training device within 24 hours after eclosion, working out 2.5 hours a day, 5 days a week with two days off, for a total of two weeks.…”